We studied by magnetic resonance imaging the incidence of associated malformations in a group of 38 patients with diagnosis of spina bifida followed in our outpatient clinic. Twenty-two children were born with spina aperta and 16 with spina bifida occulta. Tethered cord was found in the majority of patients of both groups. Syringomyelia was found in 13 patients. The craniocervical region was studied in 11 patients with diagnosis of spina bifida aperta; Chiari malformation was found in 8. The results point to the fact that asymptomatic malformations detected by MRI techniques are frequent in patients with spina bifida.